Methods and systems for recording operating information of an electronically commutated motor

ABSTRACT

A unit for recording operating information of an electronically commutated motor (ECM) is described. The unit includes a system controller communicatively coupled to an ECM. The system controller includes a processing device configured to control the unit. The unit also includes a memory device communicatively coupled to the system controller. The memory device is configured to receive and store ECM operating information provided by the processing device.

BACKGROUND OF THE INVENTION

This invention relates generally to electronically commutated motors,and more specifically, to methods and systems for recording operatinginformation of an electronically commutated motor.

Power control systems for electronically commutated motors (ECM),sometimes referred to as brushless direct current (DC) motors, areutilized to control the operation of ECMs. More specifically, aprocessing device such as a microcontroller may be utilized in a powercontrol system to control the operation of ECMs. Occasionally, in somecases because of the speeds, loads, and voltages involved with ECMoperation, an ECM or power control system may fail.

A common failure mode for microcontroller based power control systems isa cascading type failure. This type of failure may begin with a powerswitch failure, which may allow a low voltage circuit, such as a powercontrol system, to be overloaded by a high voltage and fail.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a unit for recording operating information of anelectronically commutated motor (ECM) is provided. The unit includes asystem controller communicatively coupled to an ECM. The systemcontroller includes a processing device configured to control the unit.The unit also includes a memory device communicatively coupled to thesystem controller. The Memory device is configured to receive and storeECM operating information provided by the processing device.

In another aspect, a method for providing a system to record operatinginformation of an electronically commutated motor (ECM) is provided. Themethod includes configuring a processing device to collect operatingdata from an ECM, configuring the processing device to identify at leastone of an ECM failure and a system controller failure, and configuring amemory device to receive and store the ECM operating data after at leastone of an ECM failure, a system controller failure, and a user providedshut-down instruction.

In yet another aspect, a motor system is provided. The system includesan electronically commutated motor (ECM), a controller communicativelycoupled to the ECM, the controller includes a processing deviceconfigured to control operation of the ECM, and a memory devicecommunicatively coupled to the processing device. The memory device isconfigured to receive and store operating information collected by saidprocessing device.

In yet another aspect, a method for recording operating information ofan electronically commutated motor (ECM) is provided. The methodincludes collecting operating data from the ECM, identifying at leastone of an ECM failure and a system controller failure, and storing theECM operating data after identifying at least one of an ECM failure, asystem controller failure, and a user provided power-down instruction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an electronically commutated motor (ECM)coupled to a motor controller.

FIG. 2 is a schematic diagram of a recording system, including aprocessing device and a memory device.

FIG. 3 is a block diagram of a method of recording ECM operating data.

FIG. 4 is a block diagram of a method of recording ECM operating data.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is an illustration of an electronically commutated motor (ECM)control assembly 10 including a control module 12, an ECM 14 (alsoreferred to as a permanent magnet DC brushless motor) and an end shield16. When fully assembled, end shield 16 and the components mountedthereon, are mechanically coupled to a motor shell 17. Control module 12includes a printed circuit board (not shown in FIG. 1) enclosed withinan enclosure 18. In one embodiment, the printed circuit board includes aprocessing device, for example a microprocessor, configured to controloutput signals from the printed circuit board in order to control theoperating characteristics of ECM 14.

In another embodiment, the printed circuit board is populated with aplurality of electronic components (not shown) coupled to the printedcircuit board and each other to control output signals from the printedcircuit board in order to control the operating characteristics of ECM14. The configuration of the microprocessor and the electroniccomponents is variable, based on at least one requirement of a user. Inan exemplary embodiment, control module 12 is mounted remotely from ECM14 and end shield 16. In another embodiment, control module 12 ismounted to an external surface of ECM 14. In yet another embodiment, aplurality of control modules are electrically coupled serially such thateach control module is configured to control a motor operatingcharacteristic.

Control module 12 is electrically coupled to end shield 16 by a cable22. Also, end shield 16 is electrically coupled to ECM 14 by cables.Control module 12 is also electrically coupled to a user's power supplyand interface circuitry (not shown in FIG. 1). The components mounted onend shield 16 include, in an exemplary embodiment, a bridge inverter 24which is electrically coupled to a gate drive circuit 26. Bridgeinverter 24 and gate drive circuit 26 are electrically coupled to atleast one power switch 30. Gate drive circuit 26 is electrically coupledto a motor rotor position sensing circuit (not shown in FIG. 1) by acable 34. Gate drive circuit 26 is also electrically coupled to ECM 14by a cable 36.

In an exemplary embodiment, ECM 14 includes a single phase salient polestator assembly, indicated generally at 38, including a stator core 40formed from a stack of laminations made of a highly magneticallypermeable material, and windings (not shown) of magnet wire wound onstator core 40 in a way known to those of ordinary skill in the art. Arotor 44 includes a rotor core (not shown) formed from a stack oflaminations made of a magnetically permeable material substantiallyreceived in a central bore of stator core 40. Rotor 44 and stator 38 areillustrated as being solid in FIG. 1 for simplicity, their constructionbeing well known to those of ordinary skill in the art. While FIG. 1 isan illustration of a single phase ECM and associated control circuitry,three phase ECMs and similar associated control circuitry are alsoknown.

FIG. 2 is a schematic diagram of a recording system 100 including aprocessing device 102, a memory device 104, and a protective circuit106. Memory device 104 is communicatively coupled to processing device102. In one embodiment, recording system 100 is positioned withincontrol module 12 and on the printed circuit board (not shown in FIG. 1)described above. Processing device 102 is a part of an ECM controllerthat controls the operation of an ECM. In one example, processing device102 is communicatively coupled to a device that shifts the logic levelswitching signals output by processing device 102 to the level ofvoltage used by power switches that provide power to an ECM.

In the embodiment shown in FIG. 2, processing device 102 is a PIC17C448-bit CMOS EPROM/ROM Microcontroller, available from MicrochipTechnology Inc. of Chandler. Ariz. However, as used herein, the termprocessing device, as in processing device 102, is not limited to justthose integrated circuits referred to in the art as a processing device,but broadly refers to: a processor, a microprocessor, a digital signalprocessor, a controller, a microcontroller, a programmable logiccontroller, an application specific integrated circuit, and otherprogrammable circuits.

Processing device 102 includes a Random Access Memory (RAM) configuredto temporarily store predetermined operating information. Memory device104 is configured to receive and store data from processing device 102.The data from processing device 102 may be transferred to memory device104 directly after it is received by processing device 102 ortransferred to memory device 104 after being temporarily stored in theRAM of processing device 102.

Recording system 100 also includes a communications interface (not shownin FIG. 2) that is configured to allow a user to access the data storedby memory device 104 therethrough. In an exemplary embodiment, a cableis connected to the communications interface and in communication with acomputing device, for example, a personal digital assistant (PDA) or apersonal computer. Once connected, the data stored by memory device 104is downloaded to the computing device for viewing and analysis by auser. In another exemplary embodiment, the communications interfaceincludes a wireless transmitter, for example, a radio transmitter. Acomputing device may be configured to establish a connection with thewireless transmitter and download the data stored by memory device 104to the computing device. In yet another embodiment, the communicationsinterface is configured to connect recording system 100 to a network. Auser that is able to access the network may also access the contents ofmemory device 104.

In operation, the data stored by memory device 104 is accessed by auser, in one embodiment, specifically so that a user can recover arecord of operating conditions prior to a failure, for example, at leastone of an ECM failure or an ECM controller failure. A record of theconditions prior to a failure allows a user to analyze the cause of thefailure, diagnose a specific area within a motor and motor controlsystem to fix or replace, and prevent future failures throughadjustments to failure-causing parts.

In an exemplary embodiment, processing device 102 updates a record ofmotor operating conditions at periodic intervals and stores thoserecords in the RAM of processing device 102. The periodic intervals arechosen such that the conditions prior to a failure can be recovered andanalyzed. Processing device 102 also detects when a failure is occurringor has occurred. Once a failure is detected, processing device 102 willnot overwrite the data stored in the RAM so that the conditions prior tothe failure can be recovered and analyzed.

In one embodiment, the RAM in processing device 102 stores historicinformation about conditions predetermined by a user to be of interest,for example, unusual conditions or events. These unusual conditions orevents may include, but are not limited to, a peak control moduletemperature, a fault detection event count, and a start failure count.

In operation, processing device 102 transfers the information stored inthe RAM to memory device 104. The transfer of the information stored inthe RAM to memory device 104 may occur at a set time interval, at apower-down, or when a failure is detected by processing device 102. Apower-down occurs when the power supply to the recording system isinterrupted.

In an exemplary embodiment the data received and stored by memory device104 may include, but is not limited to, a total powered time of the ECM,a total run time of the ECM, a total time operated in a cutback region,a total time over a preset thermal limit, a total number of run cycles,temperature extremes, a last operating torque level, a last operatingbus voltage, a last operating speed, a last control module temperature,a count of fault events, a count of reset cycles, a count of oscillatorstop events, a count of stall events, and “scratch-pad” events.

Memory device 104 may also be provided with, and store, productionprocess information. This information may be copied to memory device 104at the completion of a memory test, and may include a copy of a factorycalibration including passmarks and other process records. Theproduction process information is stored by memory device 104 so thatthe information will not be lost in the case of a catastrophic failure.

As stated above, the total powered time of an ECM may be received andstored by memory device 104. The total powered time of an ECM is thetotal length of time that the ECM has received power. In an exemplaryembodiment, RAM variables for powered time are incremented withinprocessing device 102 at each pass through a main program loop. Thisinformation is saved to memory device 104 at, for example, a power-downof recording system 100 or at the time of a detected failure.

The total run time of an ECM is the total length of time that the ECMhas operated at or above a preset threshold. In an exemplary embodiment.RAM variables for run time are incremented if the motor is running andthe product of speed and torque meets or exceeds a preset threshold(e.g., approximately 80% of full power). This information is saved tomemory device 104 at, for example, a power-down of recording system 100or at the time of a detected failure.

The total time in a cutback region is the total length of time that theECM has operated at a speed that exceeds a preset rate of speed. In anexemplary embodiment, RAM variables for time in the cutback region areincremented if the ECM is running and the speed exceeds the preset rateof speed (e.g., approximately 80% of the speed when ECM is operating atfull power). This information is saved to memory device 104 at, forexample, a power-down of recording system 100 or at the time of adetected failure.

The total time over a thermal limit is the total length of time that theECM has operated with the ECM baseplate temperature exceeding a presetthermal limit. In an exemplary embodiment, RAM variables for total timeover a thermal limit are incremented if the motor is running and the ECMbaseplate temperature exceeds the thermal limit setting. Thisinformation is saved to memory device 104 at, for example, a power-downof recording system 100 or at the time of a detected failure.

The total run cycles of an ECM is a count of the number of times an ECMis started. In an exemplary embodiment, RAM variables for operatingcycles are incremented every time a start is successful. Thisinformation is saved to memory device 104 at, for example, a power-downof recording system 100 or at the time of a detected failure.

Examples of the temperature extremes that may be stored ate a minimumand a maximum ECM temperature. In an exemplary embodiment, a valuerepresenting the minimum ECM temperature and a value representing themaximum ECM temperature are saved to memory device 104 at, for example,a power-down of recording system 100 or at the tune of a detectedfailure. In an exemplary embodiment, the values representing the minimumECM temperature and the maximum ECM temperature are stored in the formof RAM words.

The last operating torque level may also be stored by memory device 104.In an exemplary embodiment, a value representing the last measuredtorque level before operation ceased is saved to memory device 104 at apower-down of control module 12 or at the time of a detected failure. Inan exemplary embodiment, the value representing the last measured torquelevel before operation ceased is stored in the form of a RAM word.

The last operating bus voltage may also be stored by memory device 104.In an exemplary embodiment, a value representing the last measured busvoltage is saved to memory device 104 at a power-down of control module12 or at the time of a detected failure. The decision to store this datais made when the bus voltage has fallen below a preset limit, so anolder copy of the bus voltage measurement must be used. In an exemplaryembodiment, approximately once every 936 ms, a bus voltage reading isstored in a three level memory buffer so that the history of the busvoltage is available, and the peak bus voltage may be selected and savedto memory device 104.

A last operating speed may also be stored by memory device 104. In anexemplary embodiment, a value representing the last operating speed issaved to memory device 104 at a power-down of control module 12 or atthe time of a detected failure. In an exemplary embodiment, the valuerepresenting the last operating speed is stored in the form of a RAMword.

A last module temperature may also be stored by memory device 104. In anexemplary embodiment, a value representing the last module temperatureis saved to memory device 104 at a power-down of control module 12 or atthe time of a detected failure. In an exemplary embodiment, the valuerepresenting the last module temperature is stored in the form of a RAMword.

A count of fault events may also be stored by memory device 104. In anexemplary embodiment, RAM variables for fault events are incrementedevery time a fault intervention runs. Examples of a fault event include,but are not limited to, a circuit connection failure, a componentfailure, and a software failure. This information is saved to memorydevice 104 at, for example, a power-down of recording system 100 or atthe time of a detected failure.

A count of reset cycles may also by stored by memory device 104. In anexemplary embodiment, RAM variables for reset cycles are incrementedeach time the initialization routine runs. This information is saved tomemory device 104 at, for example, a power-down of recording system 100or at the time of a detected failure.

A count of oscillator stop events may also be stored by memory device104. In an exemplary embodiment, RAM variables for oscillator failureare incremented each time the clock fail interrupt runs. Thisinformation is saved to memory device 104 at, for example, a power-downof recording system 100 or at the time of a detected failure.

A count of stall events may also be stored by memory device 104. In anexemplary embodiment, RAM variables for operating cycles are incrementedevery time a start is unsuccessful. This information is saved to memorydevice 104 at, for example, a power-down of recording system 100 or atthe time of a detected failure.

Each type of information stored by memory device 104 may be storedseparately, but also may be stored in groups. For example, a section ofmemory in memory device 104 may be used to store a pairing of differenttypes of information. Relevant information may be extracted from notonly each individual type of information, but also from the results of acomparison of different types of information. In an exemplaryembodiment, a measured value may be paired with a representation of thetime that the measured value was obtained.

Memory device 104 may also provide storage of miscellaneous information.Storage of miscellaneous information, which may include any informationa user would like to store, is referred to herein as a scratch-padmemory function of memory device 104. The miscellaneous information mayinclude information about the system controller which can be used by asuccessor system controller in the ease the original system controlleris replaced. The information about the system controller may alsoidentify and track the motors that have been connected to the systemcontroller.

In an exemplary embodiment, at least sixteen blocks (16 byte size) ofmemory within memory device 104 are reserved for the scratch-pad memoryfunction. The scratch-pad memory function is used by the customer forstorage and retrieval of miscellaneous information via special serialcommands that specify the block number where the particular informationis stored. It is the responsibility of the system control designer toregulate this usage so that the write endurance of the part is notexceeded (e.g., 1 million cycles is typical for an EEPROM).

In the exemplary embodiment of FIG. 2, memory device 104 is anElectronically Erasable Programmable Read-Only Memory (EEPROM orE²PROM). EEPROM may be onboard processing device 102 or external toprocessing device 102. In an alternative embodiment, memory device 104is a flash memory device. Furthermore, any type of non-volatile memorydevice capable of communicating with a processing device and storingdata from a processing device may be used.

More specifically, processing device 102 may be a serial EEPROM. In anexemplary embodiment, shown in FIG. 2, an inter-integrated circuit (IIC)interface communicatively couples processing device 102 and memorydevice 104. In another exemplary embodiment (not shown in FIG. 2), aSerial Peripheral Interface (SPI) communicatively couples processingdevice 102 and memory device 104. An IIC interface requires one lessconnection between processing device 102 and memory device 104 than anSPI. The IIC interface may be advantageous because the one extraconnection necessary for an SPI requires extra components within clampcircuit 106 and an extra pin available on both microcontroller 102 andmemory device 104.

The transfer of the information stored in the RAM of processing device102 to memory device 104 consumes processor time. In an exemplaryembodiment, timer interrupts in the motor drive are allowed to runduring a transfer of information between the RAM and the memory device104. This ensures that motor operation is not interrupted by memorytransfers. Copies of the information to be transferred are loaded ontothe RAM and written back to the EEPROM at intervals or when the power isfailing.

In an exemplary embodiment, the API functions have the form of a blockmove, performed discontinuously by means of multiple passes through astate machine. More specifically, the firmware environment has a mainloop that contains a call to the state machine. If there is a transferpending, some predetermined number of words is transferred, until enoughpasses have occurred to complete the range.

In this embodiment, the lower level operations are divided into separatecalls, such that a single word transfer is done without going throughthe state machine simply by doing a series of subroutine calls. Dividingthe lower level operations into separate calls allows usage of singlewords in the device without waiting for the main loop to do thetransfer.

In an exemplary embodiment, write enable/disable functions are includedinside the API functions. The memory device 104 is left in the writedisabled state between function calls. The API function may define amaximum block transfer size allowed. In one embodiment, the API functiondefines the maximum block transfer size allowed only if the maximumblock transfer size is less than 255. Processing device 102 performs arange check comparing a string length against the maximum block transfersize.

In this exemplary embodiment, the API may also define a number of wordsto transfer per each pass through the state machine. This allows thetransfer rate to be adjusted in response to its environment.

The API may also include values for the highest and lowest RAM locationsallowed. The processing device 102 is configured to terminate a transferif the RAM destination address is outside this range.

In an exemplary embodiment, port pin data direction and level are savedat the beginning of a call and restored at the end. Saving in thismariner allows the EEPROM interface to coexist with other functions.

Referring further to FIG. 2, protective circuit 106 limits the terminalvoltage at memory device 104. Limiting the terminal voltage at memorydevice 104 prevents damage to memory device 104 and damage toinformation (i.e., loss of the information or corruption of theinformation) stored on memory device 104. Protective circuit 106 may belocated anywhere within recording system 100, and may be composed of anycomponent or combination of components, so long as recording system 100is configured in such a way that memory device 104 survives a motorfailure and/or a motor controller failure. Memory device 104 survives amotor failure and/or a motor controller failure when the informationstored on memory device 104 is not lost or corrupted and is accessibleto a user after a motor failure and/or a motor controller failure. Sinceone of the objectives of recording system 100 is to store operatingconditions immediately before a failure, memory device 104 is protectedfrom damage by high voltages through the inclusion of protective circuit106.

In another exemplary embodiment, memory device 104 includes protectivecircuitry or at least one component configured to prevent damage to theinformation stored on memory device 104. As described above, during amotor or a motor controller failure, low voltage components may beexposed to voltages high enough to damage the low voltage componentssuch as processing device 102 and memory device 104.

In an exemplary embodiment, protective circuit 106 is a clamp circuit.In the embodiment of FIG. 2, clamp circuit 106 includes a seriesimpedance 110, 112, and 114 in each of the connections between memorydevice 104 and processing device 102 and also circuitry to limit theterminal voltage at memory device 104. In an exemplary embodiment, thecircuitry to limit the terminal voltage at memory device 104 may beimplemented with Zener diodes, such as Zener diode 116. In the exemplaryembodiment of FIG. 2, four signal diodes 118, 120, 122 and 124 areconnected with the data lines, and one Zener diode 116 is connected tothe Vcc pins of processing device 102 and memory device 104. However,alternative configurations of protection circuits may be used, includinga configuration using three Zener diodes (not shown in FIG. 2). Thevalues of series impedances 110, 112, and 114 are chosen such that thefault currents conducted by signal diodes 118, 120, 122, and 124 willcause series impedances 110, 112, or 114 to open and protect memorydevice 104 by clearing the current path. As mentioned above, other typesof serial EEPROM memory may use three or four data lines which wouldeach he clamped in a similar manner in order to limit the terminalvoltage at memory device 104.

FIG. 3 is a flow chart of a method 200 of storing information usingrecording system 100. Method 200 includes configuring processing device102 to monitor ECM operation 202. As described above, motor operatinginformation may be stored on memory device 104 and may include the totalpowered time, total run time, total run cycles, etc. Each type ofoperating information predetermined to be recorded is first monitoredand collected by processing device 102.

Method 200 also includes storing 204 the operating information in theRAM of processing device 102. In one embodiment, processing device 102collects one type of motor operation information and temporarily storesthat piece of information in the RAM. After a predetermined time period,processing device 102 re-records the same type of motor operationinformation and replaces the previous information stored in the RAM withthe more recently collected information. Updating the motor operationinformation as described above ensures that should a failure occur, theinformation is stored at a point in time that is close to the time ofthe failure.

In another example embodiment, processing device 102 collects one typeof motor operation information and temporarily stores that piece ofinformation in the RAM. After a predetermined time period, processingdevice 102 collects an updated version of the same type of motoroperation information and compares it to the information stored in theRAM. Depending on how processing device 102 is configured, processingdevice 102, will either replace the older information with the updatedversion of the information, or continue to store the older information.Information such as temperature extremes (e.g. high and low ECMoperating temperatures) are stored in the RAM in this manner.

In yet another exemplary embodiment, processing device 102 monitors oneaspect of motor operation. When the aspect of motor operation beingMonitored by processing device 102 meets a specific criteria, a RAMvariable is incremented to track the number of times that the aspectbeing monitored occurred or the length of time that the aspect beingmonitored occurred. Aspects of motor operation, for example, the numberof reset cycles and the total time over a thermal limit are stored inthe RAM in this manner.

Method 200 further includes determining 206 whether a motor or motorcontroller failure is occurring or has occurred. Determining 206 whethera motor or motor controller failure is occurring or has occurredincludes configuring processing device 102 to recognize when a motor ormotor controller failure is occurring or has occurred. When a failure isdetermined, method 200 includes transferring 208 the information storedin the RAM to the memory device for secure storage of pre-failureoperating conditions.

Method 200 also includes scheduling 210 the transfer of the informationstored in the RAM to the memory device 104. More specifically, method200 includes transferring 208 the information stored in the RAM tomemory device 104 after the expiration of a preset time period. If afailure is not determined, the processing device continues monitoringmotor operation 202.

FIG. 4 is another embodiment of a method 220 of storing informationusing recording system 100. Method 220 is similar to method 200,however, method 220 includes processing device 102 directly transferring222 motor operating information to memory device 104. Method 220includes processing device 102 storing 224 certain predeterminedinformation in the RAM of processing device 102, while also storing 222certain predetermined information directly on memory device 104.

In an exemplary embodiment, processing device 102 may be configured toretrieve instructions from memory device 104. In an exemplaryembodiment, processing device 102 is configured to retrieve instructionsfrom a predetermined location within memory device 104 after a specifictype of operating information monitored by processing device 102 reachesa predetermined measurement or count. Storing contingent operatinginstructions in memory device 104 allows control of the ECM to becustomized automatically in response to a measured operating condition.

To summarize, a non-volatile memory is included in the associatedcircuitry of a processing device based ECM control. The memory allowsthe processing device to store information about the operatingenvironment history of the motor. The operating environment history ofthe motor can be retrieved from the memory and analyzed after a motor ormotor controller failure. The operating environment history of the motorcan also be retrieved at any time from the memory and analyzed in orderto aide a user in optimizing the system over time. The memory isprotected from potentially damaging voltages by circuitry designed tolimit voltage. The protective circuitry protects the memory from theeffects of a failure that may destroy the associated processing deviceor motor. Protecting the memory allows a user to retrieve from thememory the operating environment history of the motor from a time priorto the failure even after the destruction of the motor and/or theprocessing device.

Finally, the memory and processing device together provide a secondarystorage medium for information that is useful to the system controller.The processing device may be configured to retrieve operatinginstructions from the memory after receiving a predetermined level orcount of a particular type of operating data the processing device hadbeen monitoring.

The term “user”, as used herein, includes a human operator, as well assystems and applications. Therefore, the term user is not limited tobeing a human, and in many instances references a system or applicationthat includes software operating on a processor. In addition, the terms“data”, “message”, “information”, and “file” are sometimes used hereininterchangeably, and each of those terms broadly refer to information inany format.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1-23. (canceled)
 24. A unit for recording operating information of anelectric motor, said unit comprising: a motor controller communicativelycoupled to an electric motor, said motor controller comprising aprocessing device configured to control said unit, collect operatingdata from an electric motor, collect motor controller information fromsaid motor controller, and identify when a motor controller failureoccurs; a memory device communicatively coupled to said processingdevice, said memory device configured to receive and store (i) motoroperating information in response to identifying the motor controllerfailure and (ii) motor controller information for use by a successivemotor controller; and a voltage protection circuit coupled to saidmemory device, wherein said voltage protection circuit prevents highvoltage damage to said memory device.
 25. A unit according to claim 24,wherein said memory device is further configured to communicatewirelessly with said motor controller.
 26. A unit according to claim 24,wherein said memory device is further communicatively coupled to asecond processing device of a second motor controller and furtherconfigured to receive and store (i) second motor controller informationassociated with said second motor controller and (ii) second motoroperating information in response to identifying second motor controllerfailure associated with said second motor controller.
 27. A unitaccording to claim 24, wherein said memory device comprises acommunications interface configured to allow a user to access thecontents of said memory device.
 28. A unit according to claim 24,wherein said processing device comprises a random access memory (RAM)configured to temporarily store the motor operating information andmotor controller information.
 29. A unit according to claim 24, whereinsaid memory device comprises at least one of an erasable programmableread-only memory and a flash memory.
 30. A unit according to claim 24,wherein the motor operating information comprises at least one ofproduction process information, scratch-pad information, a total lengthof time said electric motor receives power, a total length of time saidelectric motor has run, a total length of time said electric motor hasoperated in a cutback region, a total length of time said electric motorhas operated with a temperature above a thermal limit setting, a totalnumber of cycles said electric motor has completed, a high operatingtemperature, a low operating temperature, a final operating torquelevel, a final operating bus voltage, a last operating speed, a lastmodule temperature, a count of fault events, a count of reset cycles, acount of oscillator stop events, and a count of stall events.
 31. A unitaccording to claim 24, wherein said electric motor comprises anelectronically commutated motor (ECM).
 32. A unit according to claim 24,wherein said memory device comprises a non-volatile memory.
 33. A unitaccording to claim 24, wherein said motor controller is integral withthe electric motor.
 34. A unit according to claim 24 wherein said motorcontroller is positioned remotely from the electric motor.
 35. A unitaccording to claim 24 wherein said voltage protection circuit comprisesone or more signal diodes that limit a terminal voltage at said memorydevice to a predefined voltage.
 36. A method for providing a system torecord operating information of a rotating electric machine, said methodcomprising: configuring a processing device to collect (i) operatingdata from a rotating electric machine and (ii) controller data from asystem controller; configuring the processing device to identify when asystem controller failure occurs; configuring a memory device to receiveand store (i) operating data in response to identifying the controllerfailure, and (ii) controller data for use by a successive systemcontroller for controlling the system upon replacement of the systemcontroller; and coupling a voltage protection circuit to the memorydevice, wherein the voltage protection prevents high voltage damage tosaid memory device.
 37. A unit according to claim 24, wherein saidmemory device is further configured to communicate wirelessly with saidsystem controller.
 38. A method according to claim 36 further comprisingconfiguring the memory device to receive and store (i) second controllerdata associated with said second system controller and (ii) operatingdata in response to identifying a second controller failure associatedwith said second system controller.
 39. A method according to claim 36wherein coupling said voltage protection circuit to the memory devicefurther comprises coupling at least one Zener diode to the memorydevice.
 40. A motor system comprising: an electric motor; a motorcontroller coupled to said electric motor and configured to communicatewith said electric motor, said motor controller comprising a processingdevice configured to control operation of said motor system, collectoperating data from said electric motor, collect motor controllerinformation from said motor controller, and identify when a motorcontroller failure occurs; a memory device communicatively coupled, tosaid processing device, said memory device configured to receive andstore (i) motor operating information in response to identifying themotor controller failure and (ii) motor controller information for useby a successive motor controller for controlling said unit; and avoltage protection circuit coupled to said memory device, wherein saidvoltage protection circuit prevents high voltage damage to said memorydevice.
 41. A system according to claim 40, wherein said memory devicecomprises a communications interface configured to allow a user toaccess the contents of said memory device.
 42. A system according toclaim 40, wherein said voltage limiting circuit comprises a plurality ofsignal diodes that limit a terminal voltage at said memory device to apredefined voltage.
 43. A system according to claim 40, wherein theoperating information comprises at least one of production processinformation, scratch-pad information, a total length of time saidelectric motor receives power, a total length of time said electricmotor has run, a total length of time said electric motor has operatedin a cutback region, a total length of time said electric motor hasoperated with a temperature above a thermal limit setting, a totalnumber of cycles said electric motor has completed, a high operatingtemperature, a low operating temperature, a final operating torquelevel, a final operating bus voltage, a last operating speed, a lastmodule temperature, a count of fault events, a count of reset cycles, acount of oscillator stop events, and a count of stall events.